Alternatives to STMicroelectronics M27C256B-15F1
STMicroelectronics M27C256B-15F1 and its qualified second sources, compared on form/fit/function, stock, lifecycle and price — the same checks Parter runs inside a BOM.
 M27C256B-15F1STMicroelectronics |  AT27C256R-70PUMicrochip Technology |  AT27C256R-45PUMicrochip Technology | +2more | |
|---|---|---|---|---|
| FFF Compatibility | Pins match the original M27C256B perfectly according to the standard JEDEC 27C256 pin configuration (Pin 1 is VPP, Pin 27 is A14).Standard 28-pin DIP package with a 0.600" row-to-row spacing matches the physical footprint of the original 28-CDIP, though it is housed in plastic (PDIP) and lacks a quartz window.32K x 8 parallel architecture, matching 5V supply range, and a faster 70 ns read access speed fully cover the original's specifications. | Standard 27C256 pin assignments are identical (Pin 1 is VPP, Pin 27 is A14).Standard 28-pin plastic DIP package (0.600" width) directly fits the original footprint.Matching 32K x 8 parallel memory organization, 5V supply, and highly backward-compatible 45 ns read access speed. | ||
 AI Summary | M27C256B-15F1 by STMicroelectronics: EPROM - UV Memory IC 256Kbit Parallel 150 ns 28-CDIP Frit Seal with Window. | This is an active, standard 256K parallel OTP EPROM that serves as a direct drop-in replacement. It offers a faster 70 ns speed grade and extended industrial operating temperature range. Because it is One-Time Programmable (OTP) in a plastic package, it cannot be erased with UV light like the windowed ceramic original, but it behaves identically in read-only applications once programmed.
| A faster 45 ns speed-grade option from the same active OTP EPROM family. It provides seamless JEDEC-compliant pin compatibility for applications requiring high-performance parallel read speeds. Similar to the 70 ns variant, it is a plastic OTP device with no UV-erase capability.
| |
| Lifecycle Status | Obsolete | Active | Active | |
| Market Availability | Discontinued | In stock | In stock | |
| REACH | REACH | REACH | REACH | |
| RoHS | RoHS | RoHS | RoHS | |
| Description | EPROM - UV Memory IC 256Kbit Parallel 150 ns 28-CDIP Frit Seal with Window | EPROM - OTP Memory IC 256Kbit Parallel 70 ns 28-PDIP | EPROM - OTP Memory IC 256Kbit Parallel 45 ns 28-PDIP | |
| Manufacturer | STMicroelectronics | Microchip Technology | Microchip Technology | |
| Type | Memory | Memory | Memory | |
| Datasheet | Open | Open | Open | |
| Lead Time | 17 weeks | 6 weeks | 7 weeks | |
| Country of Origin | KR | - | - | |
| Export Control Class Number | OBSOLETE | EAR99 | EAR99 | |
| HTSUS Code | 8542.32.0061 | - | - | |
| Moisture Sensitivity Level | 1 (Unlimited) | - | - | |
| Technology | EPROM - UV | - | - | |
| Access Time | 150 ns | - | - | |
| Memory Size | 256Kbit | - | - | |
| Memory Type | Non-Volatile | - | - | |
| Memory Format | EPROM | - | - | |
| Mounting Type | Through Hole | - | - | |
| Package / Case | 28-CDIP (0.600", 15.24mm) Window | - | - | |
| Memory Interface | Parallel | - | - |
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Related parts
| Part | Market availability | Lifecycle | Alternatives available |
|---|---|---|---|
 M27C256B-10F1STMicroelectronics | Non-stock | Obsolete | 3Alternatives availableSee Alternatives |
 M27C4002-10F1STMicroelectronics | Non-stock | Obsolete | 3Alternatives availableSee Alternatives |
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Frequently asked questions
Yes. The STMicroelectronics M27C256B-15F1 is marked obsolete, so the manufacturer has discontinued it and any remaining supply is limited to distributor stock. The qualified second sources on this page are active parts you can design in today.
The closest qualified second sources for the STMicroelectronics M27C256B-15F1 are the AT27C256R-70PU (Microchip Technology) and the AT27C256R-45PU (Microchip Technology), out of 4 matched alternatives in total. Each is compared against the original on fit, form and function in the table above.
Not always. The alternatives to the M27C256B-15F1 are matched on function but can differ in package, pinout or a key parameter, so review the fit/form/function notes in the table and the datasheet before designing one in.
The M27C256B-15F1 (STMicroelectronics) is a part in the Memory category. This page lists qualified, cross-referenced replacements for it with a side-by-side comparison.
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